1. Field of the Invention
The present invention relates to an electrical circuitry having a base element, a printed circuit board and a fastening apparatus for fastening the printed circuit board to the base element, the fastening apparatus retaining the printed circuit board by virtue of the base element being present on a top side and underside of the printed circuit board.
2. Description of the Related Art
Electrical circuitries of the type stated above are known. For example, published Korean patent application KR-2004042300-A describes a fastening apparatus that may be used to fasten a printed circuit board to a base element. To that end, a screw applies a force to the printed circuit board in the direction of the base element from one side, while counter-elements of the printed circuit board provide a counteracting force from the other side. In this manner, the printed circuit board is held at a distance from the base element without the force applied by the screw to the printed circuit board bending the printed circuit board. However, if a thermal load is applied to the electrical circuitry, varying coefficients of expansion of the base element and printed circuit board may result in thermal-related material stresses. Since the printed circuit board is firmly fastened to the base element, it is able to produce a deformation of the printed circuit board. If the electrical circuitry is exposed to continuously changing environmental conditions, i.e., in particular a constantly changing temperature, the printed circuit board and the soldering joints located on the printed circuit board may be irreparably damaged by the continuously changing material stresses and the resulting deformations. In this case, a complex fault analysis must be performed and frequently the entire electrical circuitry must be replaced.